Continued studies were made on cold-blooded vertebrates (snakes) to determine the role, if any, they might play in the ecology of western equine encephalomyelitis virus. Antigens, immune serums, and ascitic fluid have been prepared for a number of standard and "new" viral agents for inclusion in our already existing large battery of reagents used in routine and special serology. Methods of storage of these reagents are under investigation. Tissue culture was employed in the production of antigens for use in the hemagglutination-inhibition test (particularly where antigens prepared from "infected" suckling mouse brain tissue failed to yield a hemagglutinin). Diagnostic serology continued to be a function of the laboratory in response to physicians and various state public health laboratories. Emphasis has been placed on the study of tick-borne viruses. Assistance is given to the Montana State Dept. of Health in encephalitis investigations, such as isolation and identification of viruses from mosquitoes.